Recent advances in the area of behavioral medicine have identified the Type A behavior pattern as a risk factor for coronary disease (CHD). It is generally believed that heightened cardiovascular and neuroendocrine responsivity may be responsbile for the higher rate of CHD observed in Type A individuals. In an effort to reduce the risk for the development of CHD in healthy Type A individuals, and for reinfarctions in Type A patients with coronary disease, the present study is designed to test the hypothesis that a program of regular aerobic exercise will attenuate the behavioral, cardiovascular and neuroendocrine resonsivity of Type A individuals. One hundred twenty patients with documented CHD ( at Duke and Wake Forest) and 100 healthy Durham city employees will be assigned to either an exercise treatment group (1 hour; 3-5 times a week) or a control group. Upon entry and after three and six months, subjects will undergo comprehensive evaluations. Traditional risk factors of blood pressure, serum lipids and functional capacity determined by symptom-limited treadmill testing will be assessed. In addition, all subjects will receive a structured behavioral interview to evaluate the presence of the Type A behavior pattern and a set of behavioral subcomponents including speed and volume of speed, response latency, motoric activity, interruptons, and potential for hostility. Subjects will also complete a battery of psychometric tests and will be subjected to a behavioral challenge to assess cardiovascular and neuroendocrine responsivity. Additional information will be obtained to evaluate the effects of exercise on psychological well-being, functional capacity and traditional risk factors for CHD. This project has important scientific significance by proposing to evaluate how aerobic exercise can modify responses to stress. The study also has important practical significance by further defining the benefits and limitations of physical exercise training in healthy adults, and by critically examining the efficacy of aerobic exercise in cardiac rehabilitation settings in reducing risk for recurrent CHD events.